As shown in FIG. 1, a traditional magnetic field sensing device 100 is primarily composed of four magnetoresistive elements 120, 130, 140 and 150 electrically arranged to form a wheatstone bridge circuit. It is possible to measure the level of a magnetic filed substantially parallel to a substrate by reading the voltage value of the voltmeter 160. However, the traditional magnetic field sensing device could only measure the level of a magnetic field of a single direction substantially parallel to the substrate (that is X-axis or Y-axis direction) but could not measure the level of a magnetic field of a direction substantially perpendicular to the substrate (that is Z-axis).
Although with the technology nowadays it is possible to integrate two magnetic field sensing devices respectively configured to measure two magnetic fields of different axes substantially parallel to the substrate into the same substrate, these two axes are limited to X-axis and Y-axis. No publications have shown that magnetic field sensing devices respectively configured to sense X-axis, Y-axis and Z-axis can be integrated into the same substrate while preventing the performance of the Z-axis magnetic field sensing device being affected by the X-axis magnetic field or the Y-axis magnetic field.
Therefore, there is a need to propose a device on a single substrate that is capable of sensing X-axis, Y-axis and Z-axis magnetic fields so as to improve simplicity, integration and sensing precision of the magnetic sensing device.